JPH07216325A - Surface protection film - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a surface protective film which has a small increase in adhesive strength even when exposed to high temperatures and stored for a long period of time, and has good removability and releasability. A surface protective film comprising a base film made of a polyolefin-based resin and a rubber-based pressure-sensitive adhesive layer formed on one side of the base film, wherein the base film contains rutile titanium oxide and a hindered amine-based compound, and The average transmittance of light of wavelength 400-700nm of the film is 40
% Or less, a surface protective film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface protective film used for the purpose of preventing contamination and external damage of a coated steel plate, a synthetic resin molded product, or an automobile.

[0002]

2. Description of the Related Art Conventionally, a base film of polyester resin, vinyl chloride resin, polyethylene resin or the like for protecting painted steel plates, machine parts, metal household products, synthetic resin molded products, etc. from contamination and external damage. Laminates coated with rubber-based or acrylic-based adhesives that have removability are used as surface protection films, but coated steel sheets, synthetic resin molded products, automobiles for export, etc. In addition, temporary storage indoors or outdoors (usually 2 to 12 months) is often performed.

The surface protective film does not adhere to the adherend to be peeled off during transportation or storage, and can be easily peeled off when the adherend is used, and there is no adhesive residue on the adherend after peeling. Although it is desirable that the adherend does not contaminate the adherend, it is generally known that the surface protective film has a remarkably increased adhesive strength over time even if it has an appropriate adhesive strength in the initial stage of application. For this reason, after storage, it is difficult to peel the surface protective film from the surface of the adherend, and the peeling work requires labor, or peeling may occur when peeled quickly,
There is a problem that the base film is broken.

Particularly, when the surface protective film is adhered to the adherend and is, for example, placed in a high temperature condition of 60 to 80 ° C. or stored for a long time, such a tendency becomes remarkable. Become. Therefore, a method of adding inorganic fine particles to the base film to reduce the ultraviolet transmittance (Japanese Patent Laid-Open No. 4-153).
No. 287) or a method for forming a specific pressure-sensitive adhesive layer (Japanese Patent Laid-Open No. 5-98223), but it was stored for a long time on an adherend having a strong adhesive force such as a coated steel plate. In this case, there are problems that adhesive residue may occur during peeling and the film substrate may be broken.

[0005]

Problems to be Solved by the Invention
Provide a surface protection film that can be easily peeled off even after long-term storage and has no adhesive residue on the adherend and does not cause breakage of the base film.

[0006]

SUMMARY OF THE INVENTION However, the gist of the present invention is to provide a surface protection film comprising a base film made of a polyolefin resin and a rubber adhesive layer formed on one side of the base film. A rutile-type titanium oxide and a hindered amine compound, and the substrate film has an average transmittance of light having a wavelength of 400 to 700 nm of 40% or less.

The present invention will be described in detail below. Examples of the polyolefin resin used for the base film of the surface protective film of the present invention include polyethylene, polypropylene, an ethylene / vinyl acetate copolymer or a mixture thereof, and particularly, MFR 0.5 to 20 g / 1.
MFR 0.5 to 20 g / 10 min with 0 min of propylene homopolymer or ethylene component of 10 wt% or less
The polyolefin resin containing 50% by weight or more of the propylene copolymer of the ethylene / propylene copolymer is preferable in that the base material is less likely to break.

The thickness of the film may be appropriately determined depending on the composition and the application, but is usually about 20 to 150 μm. If it is 20 μm or less, the resistance to external damage may be poor, and if it is 150 μm or more, the lapping property is poor, and
It is not preferable because it is economically inferior. The titanium oxide used in the present invention needs to be of the rutile type and has an average particle size of 0.01 to 1 μm. The rutile type titanium oxide itself has good weather resistance and prevents an increase in the adhesive strength of the surface protective film after aging.

The base film of the present invention is blended with rutile type titanium oxide so that the average transmittance of light having a wavelength of 400 to 700 nm is 40% or less, preferably 30% or less, more preferably 20% or less. Is. Wavelength 400
If the average transmittance of light of ˜700 nm exceeds 40%, there arises a problem that adhesive residue occurs when the surface protective film is peeled off. The amount of rutile type titanium oxide is 6 to 50 parts by weight, preferably 1 part by weight based on 100 parts by weight of the polyolefin resin.
It is 0 to 30 parts by weight, more preferably 10 to 20 parts by weight. If the compounding amount is less than 6 parts by weight, the wavelength of the base film is 4
If the average transmittance of light of 0 to 700 nm does not fall below 40%, and if it exceeds 50 parts by weight, the improvement of the effect due to the addition of rutile type titanium oxide cannot be expected, and conversely the physical strength of the base film itself is It is not preferable because it decreases.

Examples of the hindered amine compound used in the present invention are as follows. (1) 2,2,6,6-tetramethylpiperidinyl-4
-Benzoate (2) bis- (2,2,6,6-tetramethyl-4-piperidinyl) -sebacate (3) tris- (2,2,6,6-tetramethyl-4-
Piperidine) -phosphite

[0011]

[Chemical 1]

[0012]

[Chemical 2]

(6) 1,3,8-triaza-7,7,
9,9-Tetramethyl-3-n-octyl-spiro-
[4,5] -decane-2,4-dione (7) 1,2,3,4-tetra- (4-carbonyloxy-2,2,6,6-tetramethylpiperidine) -butane (8) 1 , 3,8-Triaza-7,7,9,9-tetramethyl-2,4-dioxo-spiro- [4,5] -decane (9) tri- (4-acetoxy-2,2,6,6) -Tetramethylpiperidine) -amine (10) 4-acetoxy-2,2,6,6-tetramethylpiperidine (11) 4-stearoyloxy-2,2,6,6-tetramethylpiperidine (12) 4-benzyl Oxy-2,2,6,6-tetramethylpiperidine (13) 4- (phenylcarbamoyloxy) -2,
2,6,6-tetramethylpiperidine (14) 4- (p-toluenesulfonyloxy) -2,
2,6,6-Tetramethylpiperidine (15) Bis- (2,2,6,6-tetramethyl-4-
Piperidinyl) -terephthalate

The blending amount of these hindered amine compounds is 0.1 with respect to 100 parts by weight of the polyolefin resin.
10 to 10 parts by weight, more preferably 0.1 to 5 parts by weight. If the hindered amine-based compound is not mixed or the amount is less than the predetermined amount, the substrate may be broken when peeled after being stored for a long time. Further, when the hindered amine compound is excessively blended, the effect cannot be expected to be improved, and on the contrary, the physical strength of the base film itself is lowered, which is not preferable.

The pressure-sensitive adhesive used in the present invention is a rubber-based pressure-sensitive adhesive, and natural rubber-based or synthetic rubber-based pressure-sensitive adhesives can be used. Examples of synthetic rubber adhesives include butyl rubber adhesives and polyisobutylene adhesives. Further, known additives such as an ultraviolet absorber, an antioxidant and a lubricant can be added to the base film and / or the pressure-sensitive adhesive layer within a range that does not impair the object of the present invention.

The base film of the present invention is prepared by blending the above-mentioned rutile-type titanium oxide and hindered amine-based compound with a polyolefin resin and then using a conventionally known method such as T.
The film is produced and manufactured by a commonly used extruder such as a die and an inflation device. Further, in order to form a pressure-sensitive adhesive layer on one surface of the base film, a coating solution prepared by dissolving the pressure-sensitive adhesive in a soluble solvent such as toluene is applied onto the base film by a usual method such as a reverse coating method. , Just dry.

[0017]

EXAMPLES The present invention will be described in detail below based on examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded.

(Production of Surface Protective Film) A resin composition prepared by adding various compounds to the polyolefin-based resins shown in Table-1 in the proportions shown in Table-1 has a thickness of 50 by T-die method.
The film was formed into a film having a thickness of μm, and the pressure-sensitive adhesive shown in Table 1 was applied to the film after drying so as to have a thickness of 10 μm to obtain a surface protective film. For each surface protection film obtained, initial adhesive strength, adhesive strength after weathering test and removability,
The peelability after outdoor storage was evaluated, and the results are shown in Table-2.

The evaluation method is as follows. (1) Evaluation of initial adhesive strength The obtained surface protection film was attached to a coated steel sheet (paint: acrylic-melamine resin), and evaluated by 180 ° peel strength according to JIS K6854.

(2) Evaluation of adhesive strength and removability after weather resistance test A surface protection film was attached to a coated steel sheet and accelerated weather resistance test was carried out for 600 hours (BP63).
C.) 180 ° peel strength after exposure and removability when peeled were evaluated. The evaluation criteria of removability are as follows. Removability: ○ ・ ・ ・ No adhesive residue △ ・ ・ ・ Slight adhesive residue × ・ ・ ・ Large adhesive residue

(3) Peelability after outdoor storage A surface protection film having a size of 100 × 500 mm was attached to a coated steel plate and installed horizontally outside without any obstacles or structures around it. 6 from April to October
Stored for a month. Then, holding the shorter side of the film, the film was peeled off in the direction of the longer side. The degree of breakage of the film at this time was evaluated. The evaluation criteria are as follows. Peelability after outdoor storage: ○ ・ ・ ・ No damage to film △ ・ ・ ・ Slight damage to film (slight film remains on painted steel plate) × ・ ・ ・ Large damage to film (30 on painted steel plate) % Or more remain)

[0022]

[Table 1]

(Note 1) 1501F: Mitsubishi Kasei Co., Ltd. polypropylene (MFR 9g / 10min) 3501F: 〃 〃 (MFR 7g / 10min) CR-60: Ishihara Sangyo Co., Ltd. rutile titanium oxide R-830: 〃 〃 A-220: Anatase type titanium oxide SANOL LS-700: manufactured by Ciba Geigy Co., Ltd. (said hindered amine compound (2)) CHIMASSORB 944LD: 〃 (said hindered amine compound (4)) MARK LA-57: ADEKA ARGUS CHEMICAL (Hindered amine compound (7)) (Note 2) A: Butyl rubber adhesive (Exxon Chemical IIR 1
00 parts by weight + Exxon Chemical Co., Vistanex LM4
0 parts by weight) B: Polyisobutylene adhesive (LM manufactured by Tonex Co., Ltd.)
-MH-LC 100 parts by weight + Exxon Chemical's Vistanex LM 40 parts by weight)

[0024]

[Table 2]

[0025]

The surface protective film of the present invention can be easily peeled off even when it is attached to an adherend and left outdoors for a long period of time.
There is no adhesive residue on the adherend after peeling and the base film does not break. Therefore, it is very useful as a coated steel plate, a synthetic resin molded product, or a surface protective film for automobiles and the like.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location B32B 27/18 Z 8413-4F 27/20 A 8413-4F B60J 11/00

Claims (3)

[Claims] 1. A surface protective film comprising a base film made of a polyolefin resin and a rubber adhesive layer formed on one side of the base film, wherein the base film contains rutile titanium oxide and a hindered amine compound, and A surface protective film, wherein the base film has an average transmittance of light having a wavelength of 400 to 700 nm of 40% or less. 2. The polyolefin resin has an MFR of 0.5.
50% by weight of polypropylene resin up to 20 g / 10 min
The surface protective film according to claim 1, containing the above. 3. The base film is a polyolefin resin 1
The surface protection film according to claim 1 or 2, wherein 6 parts by weight to 50 parts by weight of rutile type titanium oxide and 0.1 to 10 parts by weight of a hindered amine compound are mixed with 00 parts by weight.